Disposable absorbent articles such as diapers, diaper pants, training pants, incontinence garments and pads as well as feminine hygiene products including sanitary napkins, panty liners and the like are in wide use today by a wide variety or users including infants, children and adults. As a result, manufacturers of such products must invest large amounts of capital in the machinery and methods for making such products. This is especially true due to the large number of variations and sizes for each of the products that are required to satisfy the consumer needs. As a result, there is a need for the equipment used to make these products to be as versatile as possible.
When making such products, it is not unusual for there to be dozens of components that go into the final product. To make these products, it is common for individual components to be cut from stock material, either on line or off line and then fed into a main forming line to mate with other components of the end product. Mating and indexing these components, especially at the very high speeds at which such machines run, is often a detailed process. In some instances the components being combined are traveling at the same speed while in other instances, one component is moving faster or slower than the others. As a result, one component must be sped up or slowed down to ensure proper indexing and attachment to yield a quality product both as to function and aesthetics. Thus there is a need for equipment and processes that will accommodate such variability in design.
One particular problem is encountered when a component being introduced into the production line is not in the proper orientation with respect to how it is to ultimately be fitted to the overall product. As a result, much effort has been put forth in designing equipment and processes that will allow some portion or portions of the product or components to be rotated from a first position or orientation into a second position or orientation to properly align with the finished product. In the context of the main manufacturing line, the travel of the product down the production line is typically referred to as the machine direction (MD) of movement and the direction at right angles to this direction is referred to as the cross-machine direction (CD). In many instances a component must be rotated 90 degrees in the same plane from the machine direction to the cross-machine direction or vice versa to properly align the component with the end product. In other situations in may be necessary to rotate a component or product to a lesser or greater degree such as, for example, 45 degree or 135 degrees to achieve a particular product design.
While there are many designs of equipment that accomplish this task, one design employs a series of rotating arms driven by a drive shaft. At the end of each of the arms is what is referred to as a transfer puck. Each of the pucks is designed to pick up a discrete piece of material and hold it with the use of a vacuum or other holding means. If need be, the individual arms can be sped up or slowed down if the substrate onto which the discrete parts are being deposited is not moving at the same speed. Once the piece is picked up by an individual puck it is then rotated to the proper orientation and then deposited onto the substrate. See for example, U.S. Pat. Nos. 5,716,478 and 5,759,340 both to Boothe et al. and 6,139,340 to Couillard et al.
When the component being deposited on the substrate is centered on the product and assembly line, this pick up, rotation and deposition process is rather simple. However, if the component must be skewed to a position that is offset from the normal line of travel of the conveying mechanism, problems arise. One solution is to physically shift the transfer equipment off the centerline of the production line and/or attempt to skew the incoming webs of material from the centerline of production. Both of these processes are cumbersome or pose problems such as web breakage and unacceptable downtimes to shift and realign equipment. As a result, there is a need for equipment and processes that will facilitate the application of offset components onto a moving web or substrate.
One example of an area where this is a particular problem is with products that are made in the cross-machine direction. Many disposable absorbent articles are made in the machine direction. By this it is meant that the longitudinal centerline of the product is parallel to the direction of movement of the assembly line and aligned with the longitudinal centerline of the assembly line. Thus, for example, if it is desired to shift or skew the position of a particular component of the end product, shifting the product is more a function of the sequential timing as to when the component is picked up, rotated and then laid down onto the assembly line. In some instances, however, the equipment is designed to make product where the longitudinal direction of the product is perpendicular to the direction of the assembly line. When this type of CD equipment is being used, shifting the location of a component can be more difficult. One example would be shifting the location of the absorbent core in a diaper or incontinence product towards the front of the product to accommodate the male anatomy. In such situations, it may be necessary to shift the incoming supply webs or stop the line to physically shift the application equipment off the centerline of the production line. A similar situation can arise when the product is being made in the machine direction but the product employs complimentary components that are equally spaced to either side of the centerline of the production equipment thus necessitating offset of the equipment to either side of the centerline.
The present invention employs a delivery and application system that allows individual components to be applied to a moving web or conveyor at an offset location from the centerline of the product and/or the production line thereby facilitating the creation of customized products that meet the particular needs of the end user.